Re: [PATCH v3 3/4] platform/x86: Add Lenovo Capability Data 01 WMI Driver

[Derek John Clark <derekjohn.clark@gmail.com>]

On Fri, Mar 7, 2025 at 3:05 PM Armin Wolf <W_Armin@gmx.de> wrote:
>
> Am 25.02.25 um 22:59 schrieb Derek J. Clark:
>
> > Adds lenovo-wmi-capdata01.c which provides a driver for the
> > LENOVO_CAPABILITY_DATA_01 WMI data block that comes on "Other Mode"
> > enabled hardware. Provides an interface for querying if a given
> > attribute is supported by the hardware, as well as its default_value,
> > max_value, min_value, and step increment.
> > v3:
> > - Add as component to lenovo-wmi-other driver.
> > v2:
> > - Use devm_kmalloc to ensure driver can be instanced, remove global
> >    reference.
> > - Ensure reverse Christmas tree for all variable declarations.
> > - Remove extra whitespace.
> > - Use guard(mutex) in all mutex instances, global mutex.
> > - Use pr_fmt instead of adding the driver name to each pr_err.
> > - Remove noisy pr_info usage.
> > - Rename capdata_wmi to lenovo_wmi_cd01_priv and cd01_wmi to priv.
> > - Use list to get the lenovo_wmi_cd01_priv instance in
> >    lenovo_wmi_capdata01_get as none of the data provided by the macros
> >    that will use it can pass a member of the struct for use in
> >    container_of.
> >
> > Signed-off-by: Derek J. Clark <derekjohn.clark@gmail.com>
> > ---
> >   MAINTAINERS                                 |   1 +
> >   drivers/platform/x86/Kconfig                |   5 +
> >   drivers/platform/x86/Makefile               |   1 +
> >   drivers/platform/x86/lenovo-wmi-capdata01.c | 140 ++++++++++++++++++++
> >   drivers/platform/x86/lenovo-wmi.h           |  19 +++
> >   5 files changed, 166 insertions(+)
> >   create mode 100644 drivers/platform/x86/lenovo-wmi-capdata01.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index cf7f4fce1a25..f6d3e79e50ce 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -13157,6 +13157,7 @@ L:    platform-driver-x86@vger.kernel.org
> >   S:  Maintained
> >   F:  Documentation/wmi/devices/lenovo-wmi-gamezone.rst
> >   F:  Documentation/wmi/devices/lenovo-wmi-other.rst
> > +F:   drivers/platform/x86/lenovo-wmi-capdata01.c
> >   F:  drivers/platform/x86/lenovo-wmi-gamezone.c
> >   F:  drivers/platform/x86/lenovo-wmi.c
> >   F:  drivers/platform/x86/lenovo-wmi.h
> > diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> > index 875822e6bd65..56336dc3c2d0 100644
> > --- a/drivers/platform/x86/Kconfig
> > +++ b/drivers/platform/x86/Kconfig
> > @@ -475,6 +475,11 @@ config LENOVO_WMI_GAMEZONE
> >         To compile this driver as a module, choose M here: the module will
> >         be called lenovo-wmi-gamezone.
> >
> > +config LENOVO_WMI_DATA01
> > +     tristate
> > +     depends on ACPI_WMI
> > +     select LENOVO_WMI
> > +
> >   config IDEAPAD_LAPTOP
> >       tristate "Lenovo IdeaPad Laptop Extras"
> >       depends on ACPI
> > diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> > index 4a7b2d14eb82..be9031bea090 100644
> > --- a/drivers/platform/x86/Makefile
> > +++ b/drivers/platform/x86/Makefile
> > @@ -70,6 +70,7 @@ obj-$(CONFIG_YT2_1380)              += lenovo-yoga-tab2-pro-1380-fastcharger.o
> >   obj-$(CONFIG_LENOVO_WMI)    += lenovo-wmi.o
> >   obj-$(CONFIG_LENOVO_WMI_CAMERA)     += lenovo-wmi-camera.o
> >   obj-$(CONFIG_LENOVO_WMI_GAMEZONE)   += lenovo-wmi-gamezone.o
> > +obj-$(CONFIG_LENOVO_WMI_DATA01)      += lenovo-wmi-capdata01.o
> >
> >   # Intel
> >   obj-y                               += intel/
> > diff --git a/drivers/platform/x86/lenovo-wmi-capdata01.c b/drivers/platform/x86/lenovo-wmi-capdata01.c
> > new file mode 100644
> > index 000000000000..0fe156d5d770
> > --- /dev/null
> > +++ b/drivers/platform/x86/lenovo-wmi-capdata01.c
> > @@ -0,0 +1,140 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * LENOVO_CAPABILITY_DATA_01 WMI data block driver. This interface provides
> > + * information on tunable attributes used by the "Other Mode" WMI interface,
> > + * including if it is supported by the hardware, the default_value, max_value,
> > + * min_value, and step increment.
> > + *
> > + * Copyright(C) 2024 Derek J. Clark <derekjohn.clark@gmail.com>
>
> 2025

Acked for all as Mario suggested.

> > + */
> > +
> > +#include <linux/cleanup.h>
> > +#include <linux/component.h>
> > +#include <linux/container_of.h>
> > +#include <linux/device.h>
> > +#include <linux/gfp_types.h>
> > +#include <linux/types.h>
> > +#include <linux/wmi.h>
> > +#include "lenovo-wmi.h"
> > +
> > +/* Interface GUIDs */
> > +#define LENOVO_CAPABILITY_DATA_01_GUID "7A8F5407-CB67-4D6E-B547-39B3BE018154"
> > +
> > +static int lenovo_cd01_component_bind(struct device *cd01_dev,
> > +                                   struct device *om_dev, void *data)
> > +{
> > +     struct lenovo_wmi_cd01 *cd01 = dev_get_drvdata(cd01_dev);
> > +     struct lenovo_wmi_om *om = dev_get_drvdata(om_dev);
>
> Why not using the *data pointer to pass the cd01 data? This way the capdata driver
> does not need to know the structure of the private data of the lenovo-wmi-other driver.
>

I can do that, sure. Seems preferable TBH as it allows me to call it priv again.

> > +
> > +     om->cd01 = cd01;
> > +     return 0;
> > +}
> > +
> > +static void lenovo_cd01_component_unbind(struct device *cd01_dev,
> > +                                      struct device *om_dev, void *data)
> > +
> > +{
> > +     struct wmi_device *om_wdev =
> > +             container_of(om_dev, struct wmi_device, dev);
> > +     struct lenovo_wmi_om *om =
> > +             container_of(&om_wdev, struct lenovo_wmi_om, wdev);
> > +
> > +     om->cd01 = NULL;
>
> I think this is unnecessary, please remove the unbind callback.
>

Acked.

> > +}
> > +
> > +static const struct component_ops lenovo_cd01_component_ops = {
> > +     .bind = lenovo_cd01_component_bind,
> > +     .unbind = lenovo_cd01_component_unbind,
> > +};
> > +
> > +static int lenovo_wmi_cd01_setup(struct lenovo_wmi_cd01 *cd01)
> > +{
> > +     size_t cd_size = sizeof(struct capdata01);
> > +     int count, idx;
> > +
> > +     count = wmidev_instance_count(cd01->wdev);
> > +
> > +     cd01->capdata = devm_kmalloc_array(&cd01->wdev->dev, (size_t)count,
> > +                                        sizeof(*cd01->capdata), GFP_KERNEL);
>
> Cast to size_t is unnecessary here.
>

Acked.

> > +     if (!cd01->capdata)
> > +             return -ENOMEM;
> > +
> > +     cd01->instance_count = count;
> > +
> > +     for (idx = 0; idx < count; idx++) {
> > +             union acpi_object *ret_obj __free(kfree) = NULL;
>
> I am not sure if the compiler frees ret_obj after each loop iteration. Did you test this?
>

No, but I'm not sure how I would. I was manually using kfree before
but was asked to change to the free macro in an earlier rev.

> > +             struct capdata01 *cap_ptr =
> > +                     devm_kmalloc(&cd01->wdev->dev, cd_size, GFP_KERNEL);
>
> Please call devm_kmalloc() on a separate line.
>

Acked.

> > +             ret_obj = wmidev_block_query(cd01->wdev, idx);
> > +             if (!ret_obj)
> > +                     continue;
> > +
> > +             if (ret_obj->type != ACPI_TYPE_BUFFER)
> > +                     continue;
> > +
> > +             if (ret_obj->buffer.length != cd_size)
> > +                     continue;
> > +
> > +             memcpy(cap_ptr, ret_obj->buffer.pointer,
> > +                    ret_obj->buffer.length);
>
> Using devm_kmemdup() would make sense here.
>

That's a cool function. Ty, I'll use it

> > +             cd01->capdata[idx] = cap_ptr;
> > +     }
> > +     return 0;
> > +}
> > +
> > +static int lenovo_wmi_cd01_probe(struct wmi_device *wdev, const void *context)
> > +
> > +{
> > +     struct lenovo_wmi_cd01 *cd01;
> > +     int ret;
> > +
> > +     cd01 = devm_kzalloc(&wdev->dev, sizeof(*cd01), GFP_KERNEL);
> > +     if (!cd01)
> > +             return -ENOMEM;
> > +
> > +     cd01->wdev = wdev;
> > +
> > +     ret = lenovo_wmi_cd01_setup(cd01);
> > +     if (ret)
> > +             return ret;
> > +
> > +     dev_set_drvdata(&wdev->dev, cd01);
> > +
> > +     ret = component_add(&wdev->dev, &lenovo_cd01_component_ops);
> > +
> > +     return ret;
> > +}
> > +
> > +static void lenovo_wmi_cd01_remove(struct wmi_device *wdev)
> > +{
> > +     component_del(&wdev->dev, &lenovo_cd01_component_ops);
> > +}
> > +
> > +static const struct wmi_device_id lenovo_wmi_cd01_id_table[] = {
> > +     { LENOVO_CAPABILITY_DATA_01_GUID, NULL },
> > +     {}
> > +};
> > +
> > +static struct wmi_driver lenovo_wmi_cd01_driver = {
> > +     .driver = {
> > +             .name = "lenovo_wmi_cd01",
> > +             .probe_type = PROBE_PREFER_ASYNCHRONOUS,
> > +     },
> > +     .id_table = lenovo_wmi_cd01_id_table,
> > +     .probe = lenovo_wmi_cd01_probe,
> > +     .remove = lenovo_wmi_cd01_remove,
> > +     .no_singleton = true,
> > +};
> > +
> > +int lenovo_wmi_cd01_match(struct device *dev, void *data)
> > +{
> > +     return dev->driver == &lenovo_wmi_cd01_driver.driver;
> > +}
> > +EXPORT_SYMBOL_GPL(lenovo_wmi_cd01_match);
>
> Please put this symbol into a namespace too.
>

Yes, I noticed the mistake right after I sent the patch.

> > +
> > +module_wmi_driver(lenovo_wmi_cd01_driver);
> > +
> > +MODULE_DEVICE_TABLE(wmi, lenovo_wmi_cd01_id_table);
> > +MODULE_AUTHOR("Derek J. Clark <derekjohn.clark@gmail.com>");
> > +MODULE_DESCRIPTION("Lenovo Capability Data 01 WMI Driver");
> > +MODULE_LICENSE("GPL");
> > diff --git a/drivers/platform/x86/lenovo-wmi.h b/drivers/platform/x86/lenovo-wmi.h
> > index 113928b4fc0f..07fa67ed89d6 100644
> > --- a/drivers/platform/x86/lenovo-wmi.h
> > +++ b/drivers/platform/x86/lenovo-wmi.h
> > @@ -45,6 +45,22 @@ enum lenovo_wmi_action {
> >       THERMAL_MODE_EVENT = 1,
> >   };
> >
> > +/* capdata01 structs */
> > +struct lenovo_wmi_cd01 {
> > +     struct capdata01 **capdata;
> > +     struct wmi_device *wdev;
> > +     int instance_count;
> > +};
> > +
> > +struct capdata01 {
> > +     u32 id;
> > +     u32 supported;
> > +     u32 default_value;
> > +     u32 step;
> > +     u32 min_value;
> > +     u32 max_value;
> > +};
>
> Please put those struct definitions into a separate header file.
>

Acked.

> Thanks,
> Armin Wolf
>
> > +
> >   /* wmidev_evaluate_method helper functions */
> >   int lenovo_wmidev_evaluate_method_2(struct wmi_device *wdev, u8 instance,
> >                                   u32 method_id, u32 arg0, u32 arg1,
> > @@ -52,6 +68,9 @@ int lenovo_wmidev_evaluate_method_2(struct wmi_device *wdev, u8 instance,
> >   int lenovo_wmidev_evaluate_method_1(struct wmi_device *wdev, u8 instance,
> >                                   u32 method_id, u32 arg0, u32 *retval);
> >
> > +/* lenovo_wmi_cd01_driver match function */
> > +int lenovo_wmi_cd01_match(struct device *dev, void *data);
> > +
> >   /* lenovo_wmi_gz_driver notifier functions */
> >   int lenovo_wmi_gz_notifier_call(struct notifier_block *nb, unsigned long action,
> >                               enum platform_profile_option *profile);